[Amps] 3 phase transformers on single phase - advice pls?

[Carl]

I run my 3 phase 208V shop equipment on 240V single phase. A 7.5hp 3 
phase motor and a compensating cap are used to achieve this. The motor 
is used as an idler so it isnt performing any work. There should be 
plenty of Internet info available. Dedicated phase converters are 
available but expensive.

Carl
KM1H



----- Original Message ----- 
From: "DAVE WHITE" <mausoptik at btinternet.com>
To: <amps at contesting.com>
Cc: <pennyanddavid at btinternet.com>
Sent: Monday, November 17, 2008 10:49 AM
Subject: [Amps] 3 phase transformers on single phase - advice pls?


> Guys
>
> I'm sure I should know the answer to this, but just can't seem to find 
> anything in my literature or on the web. A friend (G7ODR, cc'd on this 
> email) and I have scratched our heads, but the more we discuss the 
> problem, the more complex it becomes.....
>
> If I use a 3 phase transformer (either a 380v or 415v primary) on a 
> 240v single phase power supply, then what will happen in the 
> secondaries?
>
> I think the transformers that I have access to are delta input and 
> star output. They're open 3-bobbin jobs rather than potted or 
> enclosed.
>
> Can I wind the secondaries in series without overloading the 
> insulation?
> Could I wind them in parallel? Would I hit core saturation problems?
>
> So, to put a few figures on it, if it's a 12kva 3 phase 380v in, 6kv 
> out, what would happen with the various permutations if I try to wire 
> it onto 240v single phase?
>
> I'm actually looking for 4.5kv RMS out at 10kva and can get a single 
> phase one custom wound, but at a price (£950 from TEC). Anyone in the 
> UK know of a cheaper but quality source?
>
> Phone a friend, ask the audience etc.... ;-)
>
> Any ideas appreciated.
>
> cheers
>
> Dave G0OIL / K2MOO
>
> _______________________________________________
> Amps mailing list
> Amps at contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
>